In a typical Fabry-Perot-style optical sensors, various problems can occur due to thermal expansion and contraction of sensor materials that have different coefficients of thermal expansion (CTE). The CTE mismatch can occur in regions where different materials mate, such as in the interface between the metallic supporting structures and the optical diaphragm in the interferometric cavity. In addition to the CTE mismatches, the metallic support structure, which is often made of stainless steel or similar materials having a high CTE. Mismatches in CTE can cause high thermal stress and strain between parts and cause deformation, which can result in measurement error and/or cracking of the optical glass in the extreme case. Cracking and fracturing can occur at the adhesive joints between low CTE optical glasses and high CTE metallic supporting structures. The adhesive joint, for example, can become a high strain region and can fracture due to the shear or tensile stress.
Accordingly, there is a need for improved sensors that overcome such deficiencies such that CTEs can be minimized and matched to create thermally stable structures.